Speculation was mounting last week that the Government may be preparing to row back from the overhaul announced by George Osborne in the Budget.

Though Cameron's defence of the policy in the Commons was robust, making clear he wanted to "complete the work" started by Labour under Tony Blair, his official spokesman suggested there was room for manoeuvre.

The spokesman said: “I think the thing to make clear is that with the timetable we are talking about a six year period. It’s a long period of time. Clearly there’s time to discuss these issues and look at these issues.

“(Education Secretary) Nicky Morgan has already been having discussions with colleagues, with teachers, with local authorities. The goal is very clear but people are giving the impression that this is happening overnight. We are talking 2022.”

Academies are free of local authority control, get funding from central Government and tend to be "sponsored".

Corbyn cited disquiet expressed by former education select committee chair Graham Stuart and the Tory council education chief in his Oxfordshire constituency, Melinda Tilley, who said she was "fed up with diktats from above".

Parliament TV

In response, Cameron justified the reform because he wanted schools to be "run by headteachers and teachers and not by bureaucrats", and argued there is "clear evidence" the plan will work - claiming 88% of 'converter academies' are good or outstanding.

"The results are better, education's improving, I say let's complete the work,” the Prime Minister said, adding outstanding or good schools "have nothing to fear from becoming academies, but a huge amount to gain".

He added: "This is something started by the Labour Government and given rocket boosters by this Government. We've seen massive improvement because of academies and we say 'get on with it, finish the job'."